<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>弹性布局</title>
    <style>
        *
        {
            margin:0;
            padding:0;
        }
        .box{
            /* display:inline-block; */
            display:flex;
             background-color:red;
             height: 100px;
             width: 25%;
             margin-bottom: 10px;           
        }
        
        .item{
            flex:1;
            background-color: green;
            font-size:20px;
            color:black;
            display:inline-block;
             /* width: 33.33%; */
            }
        .item:nth-child(2){
            background-color: yellow;
        }
        .box:nth-last-child(2){
            background-color: blue;

        }
    </style>
</head>
<body>
    <div class="box">
        <div class="item">1</div>
        <div class="item">2</div>
        <div class="item">3</div>
    </div>
    <div class="box">

    </div>
    <div class="box">

    </div>

</body>
</html>